Automatic film processing machines presently in use in the industry utilize various mechanisms to move the film strip through the various processing steps. These include various types of roller transports, systems which rely on clamping the end or sides of a film strip, and leader-belt, leader-card and cine style processors. Although such prior systems are for the most part successful in handling films being processed, they are subject to a number of disadvantages and problem areas in which improvements would be desirable. These include the potential for damaging areas of film due to contacting the film or image area. This is especially true with fine microfilms which have very thin emulsions that are easily damaged by rough handling or contact. Also, systems which clamp the film by the edges, to avoid the central image area, do not entirely solve this problem. The contacted areas do not develop, which is a problem with school-type film in which data is recorded out to the edges of the film, it is also a problem with other types of film, because of uneven development adjacent the contacted areas which can extend out into the image.
Other problems with existing film transport systems involve the excessive carrying-over of chemical from one bath to the next, and retention of chemicals which can build up residues, requiring frequent down-time for cleaning. The large size of some processors, and the great number of components and moving parts lead to significant costs, both in original manufacturing cost and in the costs of operation and maintenance.
The use of an edge-belt for holding and transporting film has been proposed in the prior art, but it is believed such proposals were not particularly successful, and have not achieved significant use in automatic processing machines. In gripping the film along an edge, such early belt systems were subject to the problems of, zones of non-development and uneven development, and film damage due to contact along the edge and problems in control of tension in the gripping force.